Subject: RE: [PATCH 3/3] Makefile: remove an out-of-date comment

From: Felipe Contreras <[email-masked]>
Date: Thu, 17 Jun 2021 15:55:24 -0500

Ævar Arnfjörð Bjarmason wrote:
> This comment added in dfea575017 (Makefile: lazily compute header
> dependencies, 2010-01-26) has been out of date since
> 92b88eba9f (Makefile: use `git ls-files` to list header files, if
> possible, 2019-03-04), when we did exactly what it tells us not to do
> and added $(GENERATED_H) to $(OBJECTS) dependencies.

Very true.

> The rest of it was also somewhere between inaccurate and outdated,
> since as of b8ba629264 (Makefile: fold MISC_H into LIB_H, 2012-06-20)
> it's not followed by a list of header files, that got moved earlier in
> the file into LIB_H in b8ba629264 (Makefile: fold MISC_H into LIB_H,
> 2012-06-20).

I don't see the point in mentioning b8ba629264 twice, perhaps you meant:

60d24dd255 (Makefile: fold XDIFF_H and VCSSVN_H into LIB_H, 2012-07-06)

This commit also removed part of the comment:

  # XXX. Please check occasionally that these include all dependencies
  # gcc detects!

I have tried to understand what was the purpose of that comment in the
past, but I don't get it, it says:

  Dependencies on automatically generated headers such as command-list.h
  should _not_ be included here, since they are necessary even when
  building an object for the first time.

Why would it matter if we are building the object for the first time, or
rebuilding it? If we need command-list.h to build help.o once, we need
it always. What am I missing?

It seems to me this comment never made sense.

> --- a/Makefile
> +++ b/Makefile
> @@ -2503,12 +2503,6 @@ ifneq ($(dep_files_present),)
>  include $(dep_files_present)
>  endif
>  else
> -# Dependencies on header files, for platforms that do not support
> -# the gcc -MMD option.
> -#
> -# Dependencies on automatically generated headers such as command-list.h
> -# should _not_ be included here, since they are necessary even when
> -# building an object for the first time.
>  

Can we remove that extra space once we are at it?

>  $(OBJECTS): $(LIB_H) $(GENERATED_H)
>  endif

The change itself looks good to me.

Cheers.

-- 
Felipe Contreras